The frost hardiness of some clones of olive cv. Leccino

Summary

Frost hardiness of four olive clones (Olea europaea L.) belonging to cv. Leccino was studied and compared with that of a susceptible clone of cv. Moraiolo by ionic leakage. Variability of the trait was found within the clones of ‘Leccino’, some of which were statistically different from a the ‘Moraiolo’ clone at one or both temperatures tested. Only one clone showed a significant difference between ?15° and ?20°C. The ionic leakage technique is appropriate for studying changes in physical properties of membranes and its use in the screening of frost tolerant olive clones is discussed.     

Susceptibility to peach leaf curl (Taphrina deformans Berk.) Tul. in a peach germ plasm collection

Summary

The susceptibility of 1103 peach genotypes (738 dessert peach, 168 clingstone, 197 nectarines) and 152 unselected seedlings to leaf curl (Taphrina deformans) was assessed. No cultivars rated zero, which is equivalent to immunity, only six rated 1, while 62% had the highest susceptibility rating 5. Presence or absence of leaf glands and fruit type were not correlated to resistance or susceptibility. The distribution of the different fruit type and the unselected seedlings over the various susceptibility categories indicates a loss of resistance to leaf curl during selection for improved agronomic characters.     

Composting of Fish Waste with Wood By-Products and Testing Compost Quality as a Soil Amendment: Experiences in the Patagonia Region of Argentina

Composting experiments of fish processing wastes and wood by-products were conducted in the Andean-Patagonian Region. Fish wastes were mixed with sawdust + wood shavings (3:1 ratio by weight) with two replicates. Materials were mixed and placed in 220-liter PVC reactors. After 20 days, materials were remixed and reloaded in the reactors. Samples were taken at 20, 30, 40, 60, 80 and 100 day intervals and chemical analyses were made to assess predictors of compost stability. Thermophilic temperatures over 55°C were sustained long enough to satisfy the EPA requirements for pathogen reduction (72 hours). The decrease of NH₄+-N, water soluble carbon and the ratio of water soluble carbon to total nitrogen appeared to be the best parameters for predicting compost stability. Mature compost (CMP) and an organic commercial product, Lombriquen (LQN) were incubated with an Andisol and a Xeric Mollisol at a rate of lOg/kg for 16 weeks (20 to 30 percent soil moisture, 25°C) in order to estimate nitrogen and phosphorus release. Soils amended with LQN retained more P than CMP-amended soils (80 percent vs 60 percent of added Olsen-P in the Andisol and 50 vs 35 percent in the Xeric Mollisol). While N mineralization rates of LQN were variable (three to 11 percent of added total N), CMP showed constant rates for both types of soils (12 percent) and released more available N than LQN.     

Novel approach for food safety evaluation. Results of a pilot experiment to evaluate organic and conventional foods

There is evidence that organic food often contains relatively high amounts of natural toxic compounds produced by fungi or plants, whereas corresponding conventional food tends to contain more synthetic toxins such as pesticide residues, but only a few studies have evaluated the impact of their consumption on health. This study proposes a novel approach to evaluate the potential health risk of organic compared to conventional food consumption, that is, the assay of sensitive markers of cell function in vulnerable conditions. The markers utilized were intestinal and splenic lymphocyte proliferative capacity and liver acute-phase reaction, both responding to the presence of toxins. The vulnerable conditions in which body defenses can be less efficient were weaning and protein-energy malnutrition. This study reports the results of a pilot experiment on one sample of eight varieties of organically and conventionally grown wheat. Weaned rats were assigned to two groups fed conventional (CV) or organic (ORG) wheat for 30 days. Each group was divided in two subgroups of well-nourished (WN) or protein-energy-malnourished (PEM) rats. For each rat, the lymphocyte proliferation was assayed by [(3)H]thymidine incorporation after stimulation of cells with a mitogen, in a culture medium containing either commercial fetal calf serum (FCS) or the corresponding rat serum (RS) to mimic the in vivo proliferative response. The acute-phase proteins (albumin, transthyretin, transferrin, ceruloplasmin, retinol-binding protein) were measured in plasma by Western blotting and immunostaining with specific antibodies. The proliferative response of lymphocytes cultured with FCS and the amount of acute-phase proteins of rats fed the ORG wheat sample, either WN or PEM, did not differ from those of rats fed the CV wheat sample. However, the proliferative response of lymphocytes cultured with RS was inhibited in PEM-CV compared with PEM-ORG. The content of mycotoxins was highest in the organic sample, and therefore the immunotoxic effect was probably due to other contaminants in the CV wheat. In conclusion, these results indicate that the conventional wheat sample tested represented a higher risk for lymphocyte function than the wheat sample organically grown, at least in vulnerable conditions.     

Fingerprinting of three typical macrosperma Italian lentil (Lens culinaris Medik.) landraces using fluorescence-based AFLP markers

Italian lentil landraces are principally cultivated for self or local consumption. Most of them are disappearing, particularly macrosperma types by being less required by the market. A pre-requisite for the conservation and the efficient use of genetic resources is the better understanding of the extent and the distribution of the existing genetic variation, useful for future breeding programmes. Our study was undertaken to analyse and quantify the genetic diversity within and among three macrosperma Italian lentil landraces (Onano, Altamura and Villalba), using fluorescent AFLP markers. AFLP markers generated information to differentiate among closely related genotypes and group within the same cluster individuals belonging to the same landrace. The total genetic diversity (H_T), the genetic diversity within population (H_S) and the extent of differentiation between populations (D_ST) were 0.198, 0.155 and 0.043, respectively. The fixation index (G_ST = 0.219) showed that about 78% of the observed total genetic variation can be attributed to within population differences and around 22% is due to differences among populations. The gene flow estimate (N_m = 1.774) and the mean genetic distance value (0.077) suggested narrow genetic base among the analysed populations, confirming the tendency of Italian lentil landraces to group together. The present study showed that fluorescence-based AFLP technique is a biotechnological tool that can provide significant insights for research in genetic diversity of lentil landraces and their subsequent conservation and utilization in breeding programs.     

鉴定桃砧木对根癌病敏感性的叶圆片转化系统的建立

以山桃、毛桃、Ｍｉｓｓｏｕｒｉ和烟草为试材，以Ｔ２、２Ｐ和ＮＣＰＰＢ１６５１三个根癌农杆菌菌系为病原，在离体条件下，研究建立了用叶圆片转化鉴定桃砧木对根癌病敏感性的方法，探讨了光照和病原菌浓度对接种结果的影响。该系统可以在短时间内对桃砧木的感病性进行评价，筛选抗性种质，并可鉴定病原菌的致病力。